Worldlines - Butterfly Effect
by Jario5615
Summary: What if Remus hadn't forgotten to take the Wolfsbane potion the night Wormtail was discovered not to be dead? What if Sirius was now a legally free man, not stuck in hiding? See the butterfly effect in action as Harry's subsequent years at Hogwarts are very different to what is known.
1. Prologue - Wolfsbane

Remus Lupin stared wide eyed at the map which he and his three best friends had created when they had been at school. It displayed the impossible. The dot indicating Ronald Weasley was chasing a dot with a name that should not have been there.

Peter Pettigrew; who had supposedly been murdered 12 years ago.

As he stared in bewilderment at the parchment, he saw that Pettigrew was attempting to run towards the passageway that led into the Whomping Willow, the old tree that was planted when Remus himself had attended Hogwarts. He also saw that a dot was heading towards the other dots at speed.

The dot had the name of the most wanted man in the wizarding world, and a dear friend: Sirius Black.

He was about to rush out to confront his old friend, but a thought crossed his mind. He knew what day it was, and therefore considering the time - nearly 7:30 in the evening – Severus would come by soon with the Wolfsbane potion that he took to prevent his, as Sirius had liked to put it, his furry problem. And no doubt if he suddenly disappeared on a night such as tonight, Severus would certainly raise the alarm that a dangerous individual was on the loose. Therefore, after tapping the map with his wand and making the print vanish, he waited impatiently for the potion master to bring him the potion which would protect him from his unenviable monthly fate.

At exactly half past seven, a sharp knock on the office door indicated that the potion master had arrived with the potion.

"It's open" and Severus swooped through the door.

Severus Snape swooped bat-like into the room, his robes billowing behind him as he strode towards Remus. He brandished the potion from beneath his robes and placed it on the desk.

"Drink it swiftly and ensure you have drunk it well before the moon rises" Severus instructed him, almost business-like.

"Thank you again for brewing the potion, Severus" Despite bad blood running between the two men in their time at Hogwarts, Remus had tried all year to be at least cordial to Severus.

"I'm only as the headmaster instructs me to, Lupin" Snape replied coldly. Clearly the cordial attempts were not mutual. Severus swept from the room, promptly closing the office door behind him.

Remus stared at the potion as it bubbled meekly on the desk. The Wolfsbane was not the worst potion he had ever tasted, but by no means was it a pleasant drink either. He picked it up and swished it around in the goblet. After a few seconds, he gave caution to the wind, and drank it in one. He shuddered slightly as the concoction went down his throat. The potion had no immediate effects; it was more of a preventive measure. After picking up the map and placing it in a pocket of his robe, he departed for the Willow.


	2. Chapter 1 - Padfoot Free Again

Harry was bewildered by the events of the last hour or so. Not only had he learnt the truth behind who had told Voldemort where Harry's parents were hiding, but also that Sirius Black, the most wanted man in the wizarding world, was innocent. Not only that but he had discovered that two of his father's dearest friends, and that the map that he had used to sneak into Hogsmeade for the last year was a creation of his father's and his friends. The group were about to head back to the castle and deliver the very much alive Pettigrew to the Ministry, when an old grandfather clock in the Shrieking Shack struck 8. Sirius spun his head towards the sound and then spun it again in the direction of Lupin.

"Remus! Is it tonight?" Sirius asked is a quiet horror. Lupin bowed his head slightly, a look of frustration across it"

"I'm afraid so," he answered solemnly, "I had hoped that we would be able to get Wormtail back to the castle before the moon came out"

Sirius looked panicked towards his friend, but Lupin chuckled.

"Sirius, I have taken Wolfsbane already, and have you forgotten where we are?"

"Where we are...?" Sirius' brow furrowed for a few seconds as he looked around the room, but a look of recognition dawned on his face almost immediately. "But how will we get these three back to Hogwarts?" Sirius gestured towards Harry, Hermione and Ron, the latter of which was still on the bed.

"I will send word to Dumbledore; he is probably the only member of staff who will be truly unbiased in this matter"

Lupin took out his wand and stated "Expecto Patronum" and a translucent wolf emerged from his wand the wolf hung in mid-air. He then proceeded to talk to it:

"Go to Dumbledore and say: Pettigrew is alive. Sirius is innocent. We're in the Shrieking Shack. Harry, Ron and Hermione in company". He flicked his wand again, and the wolf left through the window. He turned to address Harry, Ron and Hermione.

"I'm afraid it just so happens that today is the full moon. But when we - that being myself, James, Sirius and Peter - were at school, we used this very building to hide me within when I transformed. I have also been using it whilst I have been teaching here. However, with everyone else also here for the time being, it would probably be best for me to be isolated. Hermione, if you could assist me?"

For a short moment, Hermione looked shocked that Lupin had addressed her. But she quickly regained her composure, and agreed, as if it had been a simple question in class.

"Well, see you all in the morning!" Lupin said cheerfully, as he and Hermione left the room.

Hermione returned soon after, confirming she had locked Remus inside of what had been the dining room downstairs. Harry was not sure exactly how felt. One the one hand it was a wonderful feeling to finally have family – his godfather – beyond the Dursleys, but he also felt uncomfortable with the fact that Professor Lupin was a werewolf. Since a full moon shone brightly through the window, Harry assumed that Lupin had transformed, but he could not hear anything from below indicating as such. He had no idea what a Wolfsbane potion was exactly, but he guessed since Lupin had said it helped his illness earlier in the year, that it could only be good for him tonight, even if Snape had brewed it.

The room around Harry lay sight to an interesting scene. Ron was still lying on the bed with his sprained leg, with Sirius attending to him, despite Ron saying it was feeling better. Since it had been Sirius' fault that Ron's leg was no longer functioning as intended, Harry supposed Sirius felt guilty about it. Hermione was sitting on the end of the bed, not saying much at all, although she kept glancing between Ron, Sirius and Pettigrew. The man who had not been murdered was bounded and unconscious, due to Sirius stunning him to alleviate some of anger, and had been shoved into a corner of the room, as not to disturb anyone. Harry kept his wand loosely trained on him, in case of an attempted escape, but he paid little attention as Pettigrew was out cold.

Harry had considered several times in the last few minutes asking Sirius some questions, but exactly what questions to asked escaped him. He obviously wanted to know about his father, since the two men had been best friends at school, but he also wanted to know other little things. However, those little things were currently escaping him. He tried collecting his thoughts into a coherent question but was still coming up with nothing. As he opened his mouth, a creaking noise started coming from downstairs. After a few seconds, the creaking continued up the stairs, and the Albus Dumbledore walked through the door to the old bedroom, his wand lit and raised.

The old wizard surveyed the scene in front of him for a few seconds. He first looked towards the bound Pettigrew, then at Harry with his wand trained on Pettigrew, then finally at the bed where Ron was laying.

"Well Sirius," he said at last, "It seems that the ministry has had an innocent man in Azkaban for the last 12 years"

Sirius' features relaxed for what Harry noticed was the first time, as he looked up to Dumbledore. Lupin had indeed been right in saying that Dumbledore would not attempt to apprehend Sirius on sight. Dumbledore murmured Nox and returned his wand to his robes.

"I must admit, I regret giving evidence at your trial now somewhat, however I am curious, how exactly did you escape from Azkaban? That is by no means a small feat"

Sirius then explained everything to Dumbledore. From Sirius, James and Pettigrew becoming animagi at school to support Lupin, to seeing the Weasleys in the paper, with Pettigrew as a rat on Ron's shoulder, to using his animagus to sneak into the grounds, and being helped all the time by Crookshanks. Dumbledore listened patiently throughout, occasionally twiddling with his beard. Once Sirius had finished his story, the old wizard smiled genially at him.

"Well, I must admit, I do feel guilty now for giving testimony against you at your trial, Sirius" Dumbledore said, a definite tone of regret in his voice.

"Don't worry yourself Dumbledore, I almost believed that I had killed him, what with him disappearing without a trace. If only I had not suggested to James and Lily to have Peter as their secret keeper…" Sirius fell silent, leaving a distinctly bitter taste in the air, and a heavy silence hung murkily over the room. The mention of his parents made Harry feel hollow, although considering the regretful look on Sirius' face, he was not the only one.

"Am I to assume Remus is downstairs currently?" Dumbledore asked, attempting break the silence.

"Y-yes, Professor Lupin asked me to lock him in the living room downstairs" Hermione stammered.

"Very good," Dumbledore then stood up from the battered chair he had sat in since his arrival. "We'll need to return to the castle, and hopefully avoid the Dementors. I will escort Mr. Pettigrew here back to the castle, to ensure he does not try to escape," Pettigrew quivered soundlessly. Dumbledore turned to Ron, "Whilst I could probably fix your broken leg here Mr. Weasley, I would rather leave it to Madame Pomphrey, since she'll do a far better job than I could. However, it would be best if we immobilize it for now," and with a flick of his wand, Dumbledore covered Ron's broken leg. "Miss Granger, if you could support Mr. Weasley for our journey back", Hermione nodded, and went over to Ron, who leaned on her and tentatively put some weight on his now bandaged foot.

"Now, let's return to the castle. If you would, Crookshanks". The ginger cat leapt of the bed and headed out of the room. Dumbledore, now dragging Pettigrew by the arm, followed, with Ron and Hermione behind him, and Sirius and Harry taking up the rear.

They passed the door to the Living room on the way out. Harry looked towards the door; the odd wolfish noise being heard from behind it.

"Will Professor Lupin be alright?" Harry thought aloud.

"Perfectly," Dumbledore replied from the entrance to the passage back to Hogwarts, "Whatever your personal feelings about Professor Snape Mr. Potter, I can assure you he is one of the best potion brewers I have ever met". For some reason, Harry did not find it odd that Dumbledore managed to get to the crux of his concern over Lupin's wellbeing.

* * *

The journey back was almost entirely uneventful. Pettigrew did not dare attempt to free himself from Dumbledore's grip, either out of an inability to do so or because he was petrified with fear, Harry did not know. Ron was struggling a bit with his injured leg, but with Hermione helping him along, he only grimaced when he put too much weight on it. Harry and Sirius were at the rear, walking a few paces behind Ron and Hermione. Now that the clouds had cleared, the full moon lit the way back towards the castle, and Harry wondered how he had never noticed just how bright full moons were.

As they approached the castle gates, Harry notices a group of figures standing just inside the front gates: one stout with a lime green bowler hat flanked by a pair of cloaked figures, the other with long, greasy black hair wrapped in a bat-like cloak. They were in light conversation, until they heard the footsteps of the ensemble escorting Wormtail into the castle. The stout man hurried down the steps to meet them, closely followed by the cloaked figures, and the bat-cloaked man following slightly behind.

"Dumbledore! I came calling but Severus here told me you were out in the grounds," Cornelius Fudge came into view under the moonlight, as he panted a little after his jog down the front steps, "I was just here to ask about – Merlin's Beard!" Fudge had noticed the rest of the group. He stared with a mixture of surprise and horror, first at Sirius, then at Harry, Ron and Hermione, and finally at Wormtail.

"I-Is that… Pettigrew? Peter Pettigrew?" He quietly asked Dumbledore, shock still etched into his round face.

"Indeed it is. He has eluded the wizarding world for twelve years, but he has since come out of hiding tonight" Dumbledore replied genially, "And by the fact that he is alive, that means that the most wanted man in our world cannot be guilty of a crime he could not have possibly committed. If you would accompany us to my office, then I'm sure we can clear it all up"

"Certainly. Certainly" Fudge took a handkerchief out of his pocket and wiped his brow. Clearly the shock of seeing a supposedly dead man had not worn off.

"Oh, and Cornelius, are the dementors really necessary?" For the dementors were rattling almost hungrily towards Sirius. Words seemingly lost to him, Fudge nodded, and tutted the dementors away. They floated back towards the castle.

As the group continued towards the headmaster's office, Snape, who had remained silent up until this point, began to open his mouth to say something as they reached the entrance hall, but Dumbledore cut over him:

"Severus, could you fetch some veritaserum from your stores? I think we may need it in what will most certainly be an impromptu interrogation"

"Of course, headmaster" As he left, he gave an unmistakably venomous glare to Harry, but also to Sirius. He swept down the staircase, his cape billowing behind him. As the group continued up the staircase, Sirius gave a slight chuckle.

"I see Snape hasn't changed one bit", he said quietly to Harry.

"You know Snape?" Harry asked, although not surprised by the all too familiar glare Snape had given his godfather.

"Unfortunately. We were in the same year at school, and after James I was probably the person he hated most. I'm honestly surprised he's working here now, but Dumbledore must have his reasons" He spoke in an undertone, so Dumbledore could not hear him.

When they reached the familiar Gargoyle, Dumbledore said: "Glazed Cherries", and the statue leapt aside to reveal the escalator-like staircase that led up to the office above. One by one, the group got on the stairs and rode them up to the office. Dumbledore pushed the door open and held the door open for all them. Once they were all inside, he pulled his wand out his wand and summoned a chair with a pair of manacles, and motioned for Wormtail to sit in it, as he released him from his grip. Whimpering slightly, Wormtail adhered, the manacles immediately clutching onto Wormtail's arms. He then waved his wand again and summoned half a dozen normal chairs. Each of them took a seat, and empty one there presumably for when Snape returned.

"Well Cornelius, until Severus arrives with the veritaserum, we cannot hear the tale from the horse's mouth, so to speak, but I am sure you have many other questions?" Dumbledore politely asked Fudge.

"Just a few Dumbledore" Fudge had seemingly regained his voice, "Just how are these three involved with all of this?" Fudge gesticulated to Harry, Ron and Hermione. Before either of them could speak, Dumbledore raised a hand slightly, indicating they would be better not to speak.

"Directly, they are not involved with this at all. But indirectly, I am sure you are all to aware why I let them accompany me, Cornelius" Fudge fidgeted slightly in his seat, "They were attempting to sneak out to comfort their friend Hagrid, over what happened earlier tonight, however they ran across me in the entrance hall as I was heading into the grounds myself. I had received a tip off that Sirius Black was in the grounds with evidence that he had not committed the crime he was convicted of. Due to Harry's connection, I let them accompany me, for I did not know if I sent them back to their dormitories if they would not try to sneak out again" This wasn't too far from the truth of course, they had indeed snuck out to comfort Hagrid, but the rest was mostly fiction, but the fiction was enough to convince Fudge.

Snape then entered, carrying a small vial of a clear liquid, which Harry assumed was the veritaserum that Dumbledore had requested. He was still carrying the venomous look, but it seemed to only show itself whenever he eyed Harry or Sirius directly.

"Thank you, Severus," Dumbledore moved around to the front of the desk, and took the vial from Snape, and turned to Wormtail, "Now, will you take this willingly or will I have to force it, Peter?" Dumbledore asked it quite politely, but there was a hint of coldness in his voice. Wormtail opened his mouth, indicating he would take it willingly. Dumbledore tipped the contents into his mouth, and Wormtail swallowed it.

Within minutes, Wormtail was signing his own prison warrant. He explained how he had been recruited as a spy by the Death Eaters, and how he fed them bits of information every so often. Then he explained that he was chosen by the Potters to be secret keeper, as they thought it was more likely that everyone would think it was Sirius instead. He followed by saying how he told Voldermort that the Potters were located in Godric's Hollow, and that when he went there he encounted Sirius, and knowing he would not win the fight, caused a massive explosion, cut off his finger and became his rat animagi, and hid in the sewers. He then explained how, so he wouldn't be completely cut off from the wizarding world, he found his way into the Weasleys and posed as a pet rat, but still able to hear news of Sirius' arrest, imprisonment, and eventual escape. Despite already hearing most of this already, Harry could not help but feel a burning anger towards the man who betrayed his parents. Once Wormtail had finished, the room fell silent.

"Well…" Fudge tried to break the hanging quiet, "Well, that's as good as a total confession, although this will have to be formalised by the ministry of course" He began fumbling around in his pocket and pulled out a small pouch. "Sorry to leave you so quickly Dumbledore, but this should be done a quickly as possible, at least before the Prophet catches wind of this. Could I use your fire, Dumbledore?"

"Certainly Cornelius, we wouldn't want too much to come of this twelve-year blunder, hmm?" Dumbledore flicked his wand towards Wormtail's chair, and the manacles broke free from the chair. Fudge then turned to Sirius.

"There will of course have to be a hearing to formalise the proceedings, but as of this moment Mister Black, you are a free man. I apologise on behalf of the Ministry for the last twelve years"

Sirius became elated, his face cracking into a grin.

"Thank you, Minister. I look forward to the hearing" Wormtail whimpered again. Snape had a distinctly dark look about him – clearly, he had wanted his old enemy to remain in Azkaban until the last possible moment.

Fudge bade them farewell and took some green powder out of his pocket. Pulling Wormtail into the fire with him he said clearly "Ministry of Magic" and with a billowing of green flames, disappeared.

Dumbledore then turned to Harry, Ron and Hermione.

"Now, it is late, and the three of you have had a very interesting evening. I suggest you head back to Gryffindor tower before Mr. Filch decides to do his evening rounds" The three of them nodded, although Harry felt sad to leave Sirius so soon. Dumbledore seemed to notice this "Don't worrt, you will be seeing Sirius very soon, I expect" With a wave goodbye to Sirius, the three rushed back to the Gryffindor tower, keeping half an eye out for Mrs. Norris. All three of them giving quiet exclamations as to not being punished for being out of bed.

Once they were back in the tower, they slumped into three chairs closest to the now put out fire and let out a collective sigh. Harry was torn between staying up all night discussing the last few hours, and going to bed, as he now felt exhausted. Hermione seemed to make the decision for him, and within a few minutes of sitting down, announced she was off to bed. With a glance at Ron, they too headed to bed, careful not to disturb Neville, Dean or Seamus as they got into bed.

Harry had problems sleeping that night, but not because of nightmares - he was simply too excited to sleep. He finally had a connection to his parents that wasn't a photograph or an old cloak. Both of these were still two of his most treasured possessions, but it felt good to have someone who had really known his parents to talk to. Of course, Remus had also been a good friend to his parents, but Sirius was his Godfather. It was only then he realised he now had family other than the Dursleys, which elated him further. Maybe he would be allowed to stay with Sirius instead for the summer; the Dursleys surely wouldn't mind at all.

Harry just hoped it wasn't the summer before he saw Sirius again.

* * *

A/N Sorry if the plot seems to move too quickly, I just wanted to clearly move it away from the canon events onto the alternative timeline I've constructed.

Also revised this chapter slightly, as there were a few grammatical errors, and I wasn't completely satisfied with the ending.


End file.
